pull in an ed25519 implementation and replace use of RSA in the DHT with ECC. fix up makefiles

Jamfile

@@ -565,6 +565,19 @@ KADEMLIA_SOURCES =
 	logging
 	;
 
+ED25519_SOURCES =
+	add_scalar
+	fe
+	ge
+	key_exchange
+	keypair
+	sc
+	seed
+	sha512
+	sign
+	verify
+	;
+
 local usage-requirements = 
 	<include>./include
 	<include>./include/libtorrent
@@ -621,6 +634,7 @@ lib torrent
 	src/$(SOURCES).cpp
 
 	: # requirements
+	<include>./ed25519/src
 	<threading>multi
 	<link>shared:<define>TORRENT_BUILDING_SHARED
 
@@ -632,6 +646,10 @@ lib torrent
 
 	<dht>on:<source>src/kademlia/$(KADEMLIA_SOURCES).cpp
 	<dht>logging:<source>src/kademlia/$(KADEMLIA_SOURCES).cpp
+
+	<dht>on:<source>ed25519/src/$(ED25519_SOURCES).c
+	<dht>logging:<source>ed25519/src/$(ED25519_SOURCES).c
+
 	<conditional>@building
 	<boost>system:<cxxflags>$(CXXFLAGS)